若向量BA=(2,3),CA=(4,7),则BC=_.
问题描述:
若向量
=(2,3),BA
=(4,7),则CA
=______. BC
答
∵向量
=(2,3),BA
=(4,7),CA
=BA
-CA
CB
则
=BC
+BA
=AC
-BA
=(2,3)-(4,7)=(-2,-4),CA
故答案为:(-2,-4).